The present invention relates to a device for transferring cigarette portions from a dual-rod production machine to a filter assembly machine. Here and hereinafter, the term "dual-rod production machine" is intended to mean a machine of the type described and claimed, for example, in U.S. Pat. No. 4,418,705, and which provides for feeding a filter assembly machine with two continuous cigarette rods traveling axially at substantially constant speed. At the output of the production machine, the two continuous rods are fed through a cutting head, usually a rotary type, which normally cuts both the rods into "double portions" , i.e. twice the length of the portion which, joined to the filter, forms a normal filter-tipped cigarette. The double portions, pushed from behind by the respective continuous rods, continue traveling axially to a pickup station where they are engaged successively by the transfer members of a transfer unit located between the output of the production machine and the input roller of a filter assembly machine. A double portion from each rod is picked up simultaneously by each transfer member, and the pair of double portions so formed is transferred into consecutive seats on the input roller of the filter assembly machine.
As described and illustrated, for example, in U.S. Pat. No. 4,577,644, a filter assembly machine normally comprises, as of said input roller, a series of parallel feed rollers, each having a number of peripheral seats for receiving a respective double portion and feeding it forward crosswise in relation to its longitudinal axis, i.e. perpendicular to the traveling direction of the double portion at the output of the production machine. By virtue of the double portions being fed in pairs to the filter assembly machine, and undergoing, in the process, a 90.degree. change in direction, the design and operating characteristics of the transfer unit must be such as to permit, not only said change in direction, but also correct loading of both double portions inside two consecutive seats on the input roller of the filter assembly machine.
In the case of a single input roller and a transfer unit featuring nonarticulated, independently-operating transfer members, correct loading necessarily consists in loading both double portions simultaneously (see, for example, U.S. Pat. No. 4,645,063), by virtue of the double portions and the seats on the input roller traveling in different directions, which normally only intersect at one point. Consecutive loading of the two portions (see, for example, U.S. Pat. No. 4,570,643) requires a highly complex transfer unit featuring articulated transfer members operating independently in relation to a respective supporting head, and which are unsuitable for high-output machines.
Though perfectly satisfactory, operation of the transfer unit described in U.S. Pat. No. 4,645,063, especially as regards simultaneous loading of the two double portions, is so complex as to substantially rule out any possibility of increasing the operating speed of current production machinery.
The reason for this lies in the final radial movement of the transfer member in relation to the input roller, which invariably results in damage to the cigarette portions, if performed over and above a given speed which is easily exceeded on modern production machinery.